The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 07, 1996
Filed:
Mar. 08, 1994
Isao Miyanaga, Kawachinagano, JP;
Kazumi Kurimoto, Kobe, JP;
Atsushi Hori, Moriguchi, JP;
Shinji Odanaka, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A semiconductor device includes an input/output terminal, an internal circuit connected to the input/output terminal, a first terminal for providing a first electrical potential, and a second terminal for providing a second electrical potential which is lower than the first electrical potential, the device further including: a first n-channel MOS transistor having a drain connected to the input/output terminal, a source connected to the second terminal, and a gate to be electrically connected to the first terminal; and a first switching element for switching between an electrically conductive state and a non-conductive state between the drain and the gate of the first n-channel MOS transistor, the switching element forming the electrically conductive state between the drain and the gate of the first n-channel MOS transistor when 1) a surge voltage lower than the first electrical potential is applied to the input/output terminal, and 2) an electrical potential difference between the drain and the gate of the first n-channel MOS transistor exceeds a predetermined voltage lower than a breakdown voltage of the gate of the first n-channel MOS transistor. The formation of the electrically conductive state prevents the gate oxide of the first n-channel MOS transistor from being damaged.